Vaginal creams and suppositories made with neem oil are quickly becoming the birth control method of choice in India. (Paranjapo and Paranjapo, 1993); (Garg, et al, 1993); (Riar, et al, 1993). They are non-irritating and easy to use while almost 100 percent effective. It's important to note, however, that even toxic spermicides are not 100 percent effective. When tested against human sperm neem extract (sodium nimbidinate) at 1000 mg was able to kill all sperm in just 5 minutes and required only 30 minutes at a 250 mg level. (Sharma, 1959); (Khare, 1984); (Lal, et al, 1987); (Riar, et al, 1988); (Sinha, et al, 1984). They have the added benefit of preventing vaginal and sexually transmitted diseases (Upadhyay, et al, 1990); (Garg, et al, undated); (Lal, et al, 1985); (Sinha, et al, 1984).

Neem has a proven ability to prevent pregnancy (Juneja, 1990); (Sharma, 1959a/b). Neem oil has also been shown to work well both before and after sex while some purified extracts only worked before sex as a preventative. (Riar et al, 1991) Neem oil appears to be the most effective form of neem for birth control, particularly hexane extracted neem oil. After a single injection of a minute amount of neem oil in the uterine horns, a strong cell-mediated immune response reaction produced a long term (up to 12 months) and reversible block in fertility. (Upadhyay, 1994);(Garg et al, 1994) There were no changes in menstrual cycles or ovarian function.

Neem oil has also been found to prevent implantation and may even have an abortifacient effect similar to pennyroyal, juniper berries, wild ginger, myrrh and angelica. The effects were seen as many as ten days after fertilization in rats though it was most effective at no more than three days. (Sinha, et al, 1984); (Lal et al, 1985). In a study on rats, neem oil was given orally eight to ten days after implantation of the fetus on the uterine wall. In all cases, by day 15, the embryos were all completely resorbed by the body. The animals regained fertility on the next cycle showing no physical problems. Detailed study of the rats revealed increased levels of gamma interferon in the uterus. The neem oil enhanced the local immune response in the uterus.(Mukherjee, 1996) Post coital use of neem oil as birth control does not appear to work by hormonal changes but produces changes in the organs that make pregnancy no longer viable (Tewari, 1989) (Bardham, 1991)

Years of study in India by some of the world's leading scientists resulted in the development of a neem-based polyherbal vaginal cream that has both spermicidal and anti-microbial action. The cream combines 25 per cent neem seed extract with extracts from the soap nut and quinine hydrochloride. Based on the success of these experiments, a neem-based contraceptive cream was developed by a pharmaceutical company in India. Tests of its effectiveness showed that it compared favorably with the chemical-based foams and gels. It was safer and easier to use, caused no irritation or discomfort, was nearly 100% effective, and was therefore used more frequently than the foam or gel spermicides.(Garg, 1993) The effect does not appear to be hormonal and is considered a safe and effective alternative to other methods that use hormones (Prakash, 1988); (Mateenuddin, 1986).

The studies leading to the development of these products proved that neem oil killed sperm in the vagina within thirty seconds and was effective for up to five hours. Most spermicide creams must be reapplied at least every hour (Sinha et al, 1984). An important effect of neem oil used in the vagina is that it seems to increase the antigen presenting ability of the uterine tract. This activation of the local immune cell population has a direct spermicidal effect without apparent side effect.

Men

Neem may become the first truly effective birth control "pill" for men (Riar, 1988). Neem leaf tablets ingested for one month produced reversible male antifertility without affecting sperm production or libido (Deshpande, 1980) (Sadre, 1984). In India and the United States, exploratory trials show neem extracts reduced fertility in male monkeys without inhibiting libido or sperm production (Sharma, et al, 1987).

In a test of neem's birth control effects with members of the Indian Army, daily oral doses of several drops of neem seed oil in gelatin capsules were given to twenty married soldiers. The effect took six weeks to become 100 percent effective, it remained effective during the entire year of the trial and was reversed six weeks after the subjects stopped taking the capsules. During this time the men experienced no adverse side effects and retained their normal capabilities and desires. (Vietmeyer, 1992) There were no pregnancies of any of the wives during the period of the study.

For long term birth control for men it appears that a very minute amount of neem oil injected in the vas deferens provides up to eight months of birth control. The tests revealed no obstructions, no change in testosterone production and no anti-sperm antibodies. The local lymph nodes showed increased ability to respond to infections indicating an immune response may be responsible for the birth control effect in men as it is in women. (Upadhyay, 1993)

My understanding is that neem oil can be put into a pill form, such as the ones marketed for fish oil supplements or Vitamin E supplements. Men take the pills daily and it suppresses their fertility. Is that right?